diff mbox series

[4/6] x86: Sync up tsc_timer with Linux

Message ID 20240828014429.3320011-5-sjg@chromium.org
State New
Delegated to: Bin Meng
Headers show
Series x86: Correct timer overflow and add msr/cpuid commands | expand

Commit Message

Simon Glass Aug. 28, 2024, 1:44 a.m. UTC 
Since we are using the code from Linux, update it to the newer version
in v6.11

Signed-off-by: Simon Glass <sjg@chromium.org>
---

 drivers/timer/tsc_timer.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/timer/tsc_timer.c b/drivers/timer/tsc_timer.c
index 2f2c2f27b7f..dd16ab320b2 100644
--- a/drivers/timer/tsc_timer.c
+++ b/drivers/timer/tsc_timer.c
@@ -83,7 +83,7 @@  static unsigned long cpu_mhz_from_cpuid(void)
 	if (cpuid_eax(0) < 0x16)
 		return 0;
 
-	return cpuid_eax(0x16);
+	return cpuid_eax(0x15);
 }
 
 /*
@@ -299,10 +299,19 @@  static unsigned long __maybe_unused quick_pit_calibrate(void)
 			if (!pit_expect_msb(0xff-i, &delta, &d2))
 				break;
 
+			delta -= tsc;
+
+			/*
+			 * Extrapolate the error and fail fast if the error will
+			 * never be below 500 ppm.
+			 */
+			if (i == 1 &&
+			    d1 + d2 >= (delta * MAX_QUICK_PIT_ITERATIONS) >> 11)
+				return 0;
+
 			/*
 			 * Iterate until the error is less than 500 ppm
 			 */
-			delta -= tsc;
 			if (d1+d2 >= delta >> 11)
 				continue;